M2 GEOLOGY OF EASTERN WISCONSIN. 



provided us any means of escape from this prolific source of danger, 

 it is quite certain to be found in our deep seated springs. 



There are several reasons why spring water is more likely to be 

 pure than that of wells. On the average it comes from greater depths 

 and has passed through a greater extent of the deeper strata which 

 are comparatively free from organic impurities, than has the water 

 of wells, which is usually drawn from the surface of the water level be- 

 neath the location of the wells. Artesian fountains are not here taken 

 into account. The water of wells is usually stagnant, while that of 

 springs is active, " is living water." 



There are some exceptions to the first part of this statement. Oc- 

 casionally a well is sunk upon an active, flowing, underground stream, 

 in which case the superior character of the water will usually be very 

 marked. The water of springs is not liable to so many sources of 

 contamination, and they more readily discharge impurities that may 

 find their way into them. In view of these facts, the study and utili- 

 zation of the numerous springs of the state become of much im- 

 portance. So far as possible all cities should be supplied by water 

 from springs or Artesian wells. 



The lowest noteworthy horizon from which springs arise is the 

 vicinity of the junction of the Potsdam sandstone and the Lower 

 .Magnesian limestone. The water from this source usually has a 

 .temperature of 48 to 50, and is clear and comparatively free from 

 organic impurities, but contains a small percentage of the carbonates 

 of lime and magnesia, and in some cases a very small percentage of 

 iron, with usually some silica, alumina and chloride of sodium. But 

 the combined amount of these is small, and the water is " soft," and 

 very pleasant to the taste. A small amount of free carbonic acid is 

 usually present, which enhances the grateful effect of the water upon 

 the palate and stomach. The springs from this horizon are not nu- 

 merous. Mitchell's spring near Berlin is a fine example, and deserves 

 the attention of the people of that place as a source of pure water for 

 domestic purposes, and as furnishing favorable conditions for trout 

 raising. Another notable spring of this class lies near the road be- 

 tween New London and Hortonville (S. W. J of K "W. J Sec. 28, T. 

 32, R. 15 E.), which is very much superior to the water from the 

 drift wells of those places. 



Above this horizon springs occur but rarely till we reach the junc- 

 tion of the St. Peters sandstone with the Trenton limestone. Some 

 shaly impervious layers mark this division, while the limestone above 

 is fissured and the sandstone below is porous. It hence follows that 

 the springs may arise either above or below the impervious stratum 



